This application claims priority from pending Swedish Patent Application Numbers 0002058-6 filed on May 31, 2000 and 0003546-9 filed on Oct. 3, 2000.
1. Technical Field
The present invention concerns a disc brake comprising a brake mechanism. The brake mechanism is received in a brake caliper. The caliper is furnished with an opening for receiving a bearing bracket of the brake mechanism.
The brake mechanism according to the present invention is primarily intended for a heavy road vehicle but may quite as well be used for a lighter road vehicle or a rail vehicle.
As the brake pads of the disc brake wear the position of the thrust plate or plates are normally altered to compensate for the wear. Without the adjustment of the position there would eventually be an impracticable stroke length of the brake. The position is altered by means of an adjuster mechanism, which takes up possible slack during each brake stroke. Normally there are two thrust units and the slack should be taken up in the same extent by both thrust units. Thus, the movement controlled by the adjuster mechanism has to be synchronized to give the same adjustment of both thrust units and thus avoid uneven wear of the brake pads.
2. Prior Art
It is previously known to have an adjuster mechanism to take up slack of the brake. It is also known to synchronize the controlled movement of the adjuster mechanism between two thrust units.
The brake mechanism of the present invention comprises a drive means including an adjuster mechanism, as is known in the art. Furthermore the drive means includes two thrust units. The synchronization of the thrust units is given as an additional effect of the drive means. The brake mechanism also includes a bearing bracket. The bearing bracket is to be received from the inside in an opening of the brake caliper. The adjuster mechanism is received in the bearing bracket. The brake caliper is reaching over the brake disc and has a cavity for receiving the brake mechanism.
One object of the present invention is to have a high quality concerning the function of synchronizing the adjustment movements between the two thrust units of the brake mechanism.
A further object is to have a brake mechanism, which is practical concerning maintenance and replacements.
Still a further object is to have an as compact and accurate brake mechanism as possible.
The above objects are achieved by a brake mechanism comprising a bearing bracket received from the inside in an opening of the caliper. The brake mechanism comprises an adjuster mechanism and, adjustment and reset shafts. The adjuster mechanism is actuated by a lever pin on the lever of the brake mechanism actuated by a pneumatic cylinder or the like. The adjuster mechanism is received in the bearing bracket at assembly.
In one embodiment of the invention all the parts giving the synchronization, including the adjuster mechanism are received in the bearing bracket. This means that it is possible to have a distinct hypoid drive. The drive forms one unit with the lever, synchronization shaft and adjuster mechanism.
In a second embodiment of the invention a set of gear wheels are arranged in the bearing bracket as part of the drive means. The set of gear wheels has the additional function of synchronizing the movement between the two thrust units. By using straight-toothed gear wheels there will be no oblique forces at the transfer of torque, whereby resetting of the mechanism will be made easier. Furthermore, the torque limiter of the adjuster mechanism may be smaller.
In a third embodiment of the invention parts giving the synchronization is placed under the cross bar, which gives a more compact mechanism. The driving will take place on sleeves requiring one thrust plate. The plate may be used to make sure that the pressure balance is optimal on pads having a suitable design.
The brake mechanism of the present invention is preferably pneumatically actuated, but it may also be hydraulically or electrically actuated.
Further objects and advantages of the invention will be obvious for a person skilled in the art from reading the description below.